Count how many posts have a custom field set

2 comments

1. You could run a custom query to count the amount of posts with a given key using $wpdb or more specifically using get_var(). If i assume you want to count published posts with a given key, then something like the folowing should do it..(though this is just an example).

   function get_meta_count( $key = '', $type = 'post', $status = 'publish' ) {
       global $wpdb;
       // Example code only
       // Good idea to add your own arg checking here
       if( empty( $key ) )
           return;
       $r = $wpdb->get_var( $wpdb->prepare( "
           SELECT COUNT(*) as count FROM {$wpdb->postmeta} pm
           LEFT JOIN {$wpdb->posts} p ON p.ID = pm.post_id 
           WHERE pm.meta_key = '%s' 
           AND p.post_status = '%s' 
           AND p.post_type = '%s'
       ", $key, $status, $type ) );
       return $r;
   }
   

   Echo or store the value returned as needed. If you’re intending on passing in any data that’s been requested or sent by a user, then you’ll need to add some further data checking inside the function.

   NOTE: If you’re doing this counting on an admin page, then there may be an internal function you can use instead(i can’t remember specifically which right now, but i’ll look it up if you need something admin side).

   Hope that helps in any case.

   Addition:
   I was curious after Viper posted to see how much difference there would be between the two queries, so i did each call 5 times, and recorded the time..

   $wdbb->get_var 
   
   Script Execution Time: 0.004 seconds
   Script Execution Time: 0.004 seconds
   Script Execution Time: 0.004 seconds
   Script Execution Time: 0.004 seconds
   Script Execution Time: 0.004 seconds
   
   // Yes i realise the results are all the same above, that's how they came out
   
   get_posts() 
   
   Script Execution Time: 0.035 seconds 
   Script Execution Time: 0.04 seconds 
   Script Execution Time: 0.03 seconds
   Script Execution Time: 0.027 seconds
   Script Execution Time: 0.04 seconds 
   

   I would note, when get_posts was given a meta_key it couldn’t find, then it gave results back much closer to the $wpdb speed, but still fell short, leaving the $wpdb method at least 2 times faster each time.

   Think my results are flawed? Please do perform your own tests, and should you want a copy of the code i used, you can find it in barebones form here.

   Viper does have a valid point(future proofing is always a good thing), i just wanted to show there are some measurable differences between the two methods(and if anyone sees a problem with my approach, please feel free to let me know).

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2. I’d recommend using get_posts(). It’ll use up more memory than directly querying the database as it’ll be returning the full post objects, but it has the advantage of being essentially future proof as you’re using the API.

   $meta_posts = get_posts( 'meta_key=foobar' );
   $meta_post_count = count( $meta_posts );
   unset( $meta_posts);
   

   See the query_posts() docs for a full list of arguments that you can use and a ton of great examples.

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